---
title: "Accessibility Checker Rule Help: combobox_active_descendant"
---
import "../../../styles/ToolHelp.scss"
import { CodeSnippet, Tag } from "carbon-components-react";

<div className="toolHelp">
<Row>
<Column colLg={16} colMd={8} colSm={4} className="toolHead">

### Active descendant focus is not set correctly within the combobox or related popup

<div id="locLevel"></div>

'aria-activedescendant' must be used to define focus within the combobox popup, except when using a dialog popup

</Column>
</Row>
<Row>
<Column colLg={11} colMd={5} colSm={4} className="toolMain">

### Why is this important?

A combobox is a UI interactive component that combines an input and another element, such as a listbox
or grid, that can dynamically pop up to help the user set the value of the input. When a combobox 
receives focus, the focus should be set on the text `<input>` element. Unless using a `dialog`
popup, the `aria-activedescendant` must be used to identify the currently focused selection in the
popup, so people who use assistive technologies are able to accurately navigate and interact with the content.

<div id="locSnippet"></div>

### What to do

* Unless the `has-popup` attribute value is `dialog`, set the active descendant focus using the `aria-activedescendant` attribute only on the combobox’s `<input>` element.

Alert: The guidance for combobox is changing significantly in WAI-ARIA 1.2 due to problems with implementation of the WAI-ARIA 1.1 pattern. The recommended combobox pattern for WAI-ARIA 1.2 is:

<CodeSnippet type="multi" light={true}> &lt;label for="tag_combo"&gt;Tag&lt;/label&gt;
  &lt;input type="text" id="tag_combo"
      role="combobox" aria-autocomplete="list"
      aria-haspopup="listbox" aria-expanded="true"
      aria-controls="popup_listbox" aria-activedescendant="selected_option"&gt;
   &lt;ul role="listbox" id="popup_listbox"&gt;
      &lt;li role="option"&gt;Zebra&lt;/li&gt;
      &lt;li role="option" id="selected_option"&gt;Zoom&lt;/li&gt;
   &lt;/ul&gt;</CodeSnippet>

Note, example code includes material copied from or derived from [W3C, Accessible Rich Internet Applications (WAI-ARIA) 1.2 W3C Working Draft 18 December 2019](https://www.w3.org/TR/wai-aria-1.2/#combobox). Copyright © [2013-2019] W3C® (MIT, ERCIM, Keio, Beihang).

</Column>
<Column colLg={5} colMd={3} colSm={4} className="toolLeft">

### About this requirement

[IBM 4.1.2 Name, Role, Value](https://www.ibm.com/able/requirements/requirements/#4_1_2)
[WAI-ARIA v1.2 Authoring Practices - Combobox](https://www.w3.org/TR/wai-aria-practices-1.2/#combobox)

### Who does this affect?

* People using a screen reader, including blind, low vision and neurodivergent people

</Column>
</Row>
</div>

export default ({ children, _frontmatter }) => (<React.Fragment>{children}</React.Fragment>)
